Brake shoe equalizing device



jam, M W36.. J. L. NALL mm BRAKE SHOIE EQUALIZING DEVICE Filed Febf4, 1955 515* Velltiorii,y the brakeU shoeA equaliziiigAr device iSA Patented Jan. '14, 1936 UNITED STATES PATENT GFFICE 2,027,874 BRAKE siren EQUAi-.Iznvd Diivicc Jolinfli. Nall, Danville, Va. Application February 4, 1935, serial No. 4,949

3 Claims.

Trie invention relates" to a, orare shoe" equaiiz; ingA device and is continuation in part `of an application ni'ed'bv me March 2, 1932i, serieu No; 'z'1`3g722".

The object' ofA the present inventionis to provide a-siniple, practical andefficient brake shoe equalizirig device of strong, durable and cornparativelv inexpensive construction designed Afor use on various types of rhotor vehicles and having. rneans for equalizing the pressure between the Brakesloes adapted for use on vehicle ]Qrakes Having` brake shoes of? either the expanding or contracting:- rype.

With these andu othei" objects in view, the invtion consists in the construction and novel conhination and arrangement of parts hereinafter fuiiy described, illustrated in the accompanying drawing and pointed Aout in the claims heretoY appended, it being nnderstcod that various changes' in the forni, proportions and minor details'of construction may be resortedto without departing fromwthe spirit or sacricing any fthe advantages of the invention.

In the drawing:

Fig-ure 1 is a transverse sectional View of a portion of the brake equalizing mechanism shown and described in theaforesaidI applica t'iori and illustrating? the manner of mounting the housing and. the brake shoe operating rock shaft on the front axle of a vehicle.

Figure 2 is an enlarged elevation of the brake shoe equali'zing device having contracting brake shoes.

Figure 3`isa transverse sectional viewof the sfnrie`-A taken through one ofthe brake shoe actating levers.

Figure 4 is an` elevation of the brake shoe edualiiiig device lhaving expanding brake shoes.

ligure4 isa transverse sectionallview of the saine through one of the brake shoe actuating levers;

Figure a detail view of onelof the contracting brake shoes.

Figure 7`- is asimilar view of one of the expanding brake shoes- Figre? is a detail ViewV of one of the levers fi operating the contracting brake shoes..`

Figure 9"is a detail view of one of the levers forat':tuatiihgv one Voff` the expanding brake shoes.

Figure" 1()' 'i'sl a detail View illustrating a modifi)- cation of `tlie"lever for actuating the expanding biakeshoe In" the accompanying drawing inwhich is il'- llst'atdsthe" Drferrdeibodineit of the iiiwheels or e veriioie" are of the saine construction, `5

adescription" of che off thebrake shoe equa-lizing devices or brake units will besuci'e'nt" to a f ll understanding of the operationY of all of thbi/ke u'IltS f Vehicle. v

Each brake' unit comprises inV its e0'nstrlictofl`` a Brake h'c'iusi'rgv 3 on' which are fulcruined at thein ends on suitable studs or pivots 4 and i5'prairieshoeVA actuating levers 6 and I Vwhich are c'nn'e'cted at their outer ends to brake shoes 8 and 9' and which` at' their outer" portions operate recesses-A 8@ arid'.l The brake levers iil and i extend outwardly from their pivots 4 and 5 to" the-periphery of the brake housing 'v'i'ilfiicli'sv provided with the said recesses il'l and Q and each brake shoe operating lever is suitably secured" to" one of the brake shoes at one end thereof and the" said brake Shoe is provided at its' other' end withan angularly disposed lug or enlarginet I'0` having a slot I I for the reception of a relatively fixed stud I2 which is adapted'when' the brakeV shoe actuating lever is Os'cillated t'ocais'a rnvement of the brake shoe toward Or'fil the brake dilliii I3 WithrWhcl'l. it is associated, according to the direction of tlierfiovement of the brake shoe actuating lever. The brake shoe normally, when the brake is not applied, is arranged in spaced relation with the b r'ake' dr'n and when the brake shoe actuating leveis Inoved in a direction to apply the brake the brake shoe rnoves'inwardly with respect to the brake' tliroughA the action of the vangulaily" reltd`- slot II of the lug or` enlarge rn'e'nt I B' andthstud I2. The terminal portions I4` of' the brake'shoes adjacent the lugor enlargeirent I extend circumierentially 'beyond tlieiidof the lug orenlarg'ement VIIJ and partake of'thegeiieral curvature ofthe brake shoe.

Wheithe brake shoe isrused for a contracting brake, the lug I will be larranged at an acute angle to theterminal portion le at the outer side' of the brakeshoe, as clearlyillustrated in Figure 6' ofthe drawing, and when the brake shoe isusd as an expanding brake the lug will be arranged at an obtuse angle toi the terminal portion at the side of the brakeshoe, as clearly sho-wn in Figure 7 of the drawing.

The' lever l is connected with one end of a brake shoe edualizing lever I by alink I6 and the other end of the brake shoe equalizing lever I5' is connected by a link i68L with a pivoted lever I 'I fulcrumed intermediate its ends at I8 on a suitable stud of the brake housing and connected with the lever 6 by a link I9 pivoted at its ends to the lever B and to the lever I1. The brake shoe equalizing lever l is centrally connected by a suitable pivot 2l with an arm 22 of a transversely disposed brake shoe operating rock shaft 23. The arm 22 which is located at the outer end of the rock shaft 23 preferably operates in an opening or recess 22a of the brake housing in order that the levers and the links of the brake shoe equalizing device may be located contiguous to the housing. The brake shoe operating rock shaft 23 is also provided with an operating arm 25 which is connected with the brake equalizing mechanism of the aforesaid application. The rock shaft 23 is mounted in the brackets 21 of the front axle and any-number of bearings or brackets may, of course, be provided for the rock shaft 23, which may be mounted in any other desired manner. The rock shafts of the rear brake units of a brake equalizing mechanism are designed to be mounted in suitable bearing brackets as explained in the aforesaid application, and to extend through an opening in the rear axle housing.

The front rock shaft 23 may be composed of inner and outer sections connected by a universal joint 28 of any desired character to render the front rock shaft ilexible in character and to enable it to yield to the steering action of the front wheel but any other suitable means may, of course, be provided to permit the necessary movement of the spindle 29 of the front axle in the turning thereof. Any suitable form of universal joint may be employed and as the front spindle may be mounted in any desired manner detailed description of the same is deemed unnecessary and the universal joint Where desired may, of course, be omitted.

When the rock shaft 23 is partially rotated to apply the brake, the arm 22 will swing in an arc as indicated by the dotted line in Figure 2 of the drawing and the brake shoes will be moved inwardly and caused to engage the brake drum i3 associated with the brake shoes. When the brake is released, the brake shoes are positively carried out of engagement with the brake drum by means of coiled springs 30 connected with the brake housing and with the brake shoe actuating levers 6 and 1, as clearly illustrated in Figure 2 of the drawing. The levers and links will equalize the pressure between the brake shoes and the brake shoes will be engaged with the brake drum with equal pressure irrespective of the character or condition of the brake lining 3l and even should the brake lining of a brake shoe be entirely worn away the pressure of the brake shoes will be equalized by the equalizing mechanism of the brake unit and as soon as the brake is released the brake shoes will be carried out of engagement with the brake drum.

Both the contracting and expanding brake shoes are readily detachable to enable them to be readily and easily removed and replaced for renewing brake linings or other repair Work necessitating their removal and for this purpose the studs l2 are designed to be equipped with Cotter pins or other detachable fastening means and the brake levers 6 and 'I are provided with integral transverse arms or studs 6a and le which are arranged in elongated or elliptical openings of lugs 8 and 32EL of the contracting and expanding brake shoes 8 and 32 respectively. The lugs 8 and 32a may have round or any other shaped openings and they are located a short distance from the adjacent ends of the said brake shoes S and 32. The arms or studs 6 and 'la are designed to be provided with cotter pins or other suitable fastening devices to enable the adjacent ends of the brake shoes to. be readily and easily disconnected from the levers 6 and l. By disconnecting the brake shoes from the levers E and 'I and from the studs l2, the brake shoes may be readily and easily detached. Also the actuating arm 22 of the rock shaft is detachably secured to the rock shaft in any suitable manner to enable it to be readily placed on and removed therefrom in assembling the parts and when otherwise required, The members of each pair of brake shoes of both the expanding and contracting type are separated a sufficient distance to enable them to move freely and Without interference into and out of engagement with the associated brake drum and in practice the brake shoes may, of course, be of any desired length to suit the size of the brake drum with which they are to be used.

When the equalizing mechanism of the brake unit is applied to expand brake shoes 32, the brake shoes will be reversed as illustrated in Figure 4 of the drawing in order that the levers 6 and l may actuate the brake shoes in the proper direction for expanding the same. The contracting brake shoe actuating levers 6 and 'l have an oiset 33 at their outer portions, as clearly illustrated in Figure 8 of the drawing, to enable them to lit around the brake drum, and the brake shoe actuating levers are preferably provided intermediate their ends with openings 34 and 35 for the links I6 and I9 of the brake shoe equalizing mechanism. Cotter pins or any other suitable means may be provided Ior the pivots or the linkage which connects the rock shafts With the brake shoes so that any of the parts may be readily removed and replaced when required.

What is claimed is:

1. In combination with a brake drum, brake shoe equalizing means comprising a pair of brake shoes, substantially radially arranged levers located at opposite sides of the center of the brake drum and pivotally mounted at their inner ends and each pivoted at its outer end to one of the brake shoes, an operating rock shaft having an arm, an equalizing lever centrally pivoted to the arm of the rock shaft and arranged to be carried through an arc by the rock shaft, a pair of diverging links pivoted at one end to the ends of the equalizing lever and having their other ends located at opposite sides of the center of the brake drums, and means for connecting the last mentioned ends of the diverging links with the brake shoe actuating levers.

2. In combination with a brake drum, brake shoe equalizing means comprising a pair of brake shoes, substantially radially arranged levers located at opposite sides of the center of the brake drum and pivotally mounted at their inner ends and each pivoted at its outer end to one of the brake shoes, an operating rock shaft having an arm, an equalizing lever centrally pivoted to the arm of the rock shaft and arranged to be carried through an arc by the rockshaft, a pair of diverging links pivoted at one end to the ends of the equalizing lever and having their other endsy located at opposite sides of the center of the brake drum, one of the diverging links being pvoted directly to one of the brake shoe actuating levers, and a lever pivoted to| the other diverging link and having a link connection with the other brake shoe actuating lever.

3. In combination with a brake drum, brake shoe equalizing means comprising brake shoes' provided at one end With an angularly disposed lug having a slot, each brake shoe being provided at the other end with an elongated opening, fixed studs arranged in the slots of the lugs for causing inward andl outward movement of the brake shoes, radially arranged brake shoe actuating levers located at opposite sides of the center of the brake drum and pivotally mounted at their inner ends and provided at their outer ends with pivots arranged in the elongated openings of the brake shoes, an operating rock shaft provided with an arm, an equalizing lever centrally pivoted tol the arm of the rock shaft and arranged to be carried through an arc by the rock shaft, and a pair of diverging links pivoted at one end to the ends of the equalizing lever and connected at their other ends with the 10 brake shoe actuating levers.

JOHN L. NALL. 

